The present invention relates to a method for mounting electronic parts on printed boards.
With the recent remarkable progress in electronics, printed board units (electronic circuit packages) constructed by mounting electronic parts on printed boards have come to be widely used not only for electric products but also for other products in various fields and there is an increasing demand for the same. In the part insertion work in fabricating the printed board unit, when handling electronic parts with leads such as ICs, a dedicated automatic inserting machine is often used to have the leads of the parts inserted into the through holes made in a printed board. However, it is not always possible to insert parts into through holes automatically due to technical and economic limitations. Whenever automatic insertion is impossible, for example with such parts as special form parts and those in the dead space of the automatic inserting machine, or units of which the produced quantity is very small are assembled, the work is performed manually. For this reason, a highly efficient method for manually assembling printed board units is strongly demanded.
The method for mounting electronic parts on a printed board by manual operation in the prior art was performed following the procedures described below. First, the drawing number of a part (part number) is read from the part delivery slip attached to the part taken out from a parts box, the part of that number is detected from the parts list as shown in FIG. 1, and the corresponding part symbol is read. Then, reference is made to the list of sequence of insertion as shown in FIG. 2 and the position of insertion of the part with that part symbol is detected from a mounting drawing, not shown, and the electronic part is inserted into the position on the printed board.
An assembling method in which prearrangement work of electronic parts to be inserted is made in advance and then a plurality of printed boards are assembled was also practiced. Also in this assembling method, a parts list, list of sequence of insertion, mounting drawing, and so forth are prepared first. Then, the part drawing number of the part picked out from a parts box is read by the eye and the parts list as shown in FIG. 1 is searched for that part number. Then, a part symbol according to the parts list is attached to the part bag 1 that was taken out and the bag is put into a parts prearrangement box as shown in FIG. 3B, in the order of the part symbol. Then, the parts prearrangement boxes 3 are piled up in the order of insertion as shown in FIG. 3C, and thereby prearrangements of the parts according to the sequence of insertion are made. After such prearrangements have been made, a deficient parts list for insufficient parts is made, and thus the prearrangement work is completed. After the part prearrangements have been completed, the parts are taken out in the prearranged order from the part prearrangement box 3 for the first assembling process, and the parts are inserted into positions on the printed board with reference to the mounting drawing. These operations are repeated and thus assembly of the printed board is accomplished.
In the method of mounting electronic parts on printed boards by manual operation practiced in the prior art as described above, great man-hours were required for comparison of the parts with the parts list, location of the positions of insertion, and the like, and it was a problem with it that extremely long time is taken for assembling printed board units. In the method of mounting without making prearrangements, wrong insertion or the like was possible to be made and hence reliability on the insertion work was low. If the prearrangement work is made, the wrong insertion of parts can be prevented but extremely long time is required for the prearrangement work.
In order to overcome these defects, there is proposed a method for mounting electronic parts on a printed board using a computer, an optical indicator controlled by the computer for indicating a position of insertion of a part on a printed board, and a parts locator with a plurality of pockets rotatably controlled by the computer. In this mounting method, the parts to be inserted are sorted first and each of the sorted parts are put in their respective pockets of the parts locator. Then, while data of pocket numbers of the parts locator and data of kinds of the parts contained in the pockets are input to the computer, the data of kinds of the parts to be inserted into positions on the printed board and data of the positions of insertion are also input to the computer. When an insertion work starting signal is input to the computer, one pocket of the parts locator is opened and the optical indicator optically indicates the position of insertion of the part. The operator inserts parts one after another into optically indicated positions. When insertion of one kind of parts has been finished, the parts locator is rotated, whereupon the operator takes out other parts from the then opened pocket and inserts the parts into the positions indicated by the optical indicator. By the above described conventional method using the optical indicator and parts locator, the efficiency of the mounting work is greatly improved because the operator need not make comparison of the parts with a parts list, detection of the positions of insertion, and so forth. However, in the described conventional method, there was a problem that it was required first to sort parts to be put into each of the pockets and then to put the sorted parts into the pockets and it was also required to make laborious data inputting work each time to have the data of the pocket number of the parts locator and the data of kinds of the parts contained in each of the pockets input to the computer.